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Garden Q&A: Work fast to salvage frozen oranges

Associated Press Citrus growers only have about 24 hours to get frozen oranges off the tree and process them into juice.

Q: I was told that oranges that freeze while still on the tree are not good to eat. Can the frost-injured fruit be juiced and frozen for use later?

A: When oranges are frozen on the tree, growers have a short time (about 24 hours) to get the fruit off the tree and process it into juice. After that time, the fruit deteriorates on the tree, and quality is ruined.

Basically what has happened is that the small vesicles or sacks that hold the juice of the fruit have been broken by the freezing, i.e., as the fruit freezes, it expands and these membranes are broken. Therefore, the juice runs out of the fruit and is exposed to all sorts of organisms that break it down.

The juice that is frozen in the stores is from processed juice that is concentrated. Additionally, juice from navel oranges does not store well. It must be consumed very quickly after juicing, or it will oxidize and become bitter.

Q: Poison ivy is growing on my trees? What's the best way to get rid of it?

A: Poison ivy (Taxicodendron radicans) can be identified by its compound leaf consisting of three leaflets which are sometimes lobed. The leaflets are 2 to 4 inches long with pointed tips. The plant grows as a shrub or as a woody vine. In late summer, the plant may produce waxy grayish-white berries. In fall, leaves turn red or orange.

You can get rid of poison ivy by hand-pulling (wear gloves, a long-sleeved shirt and long pants to prevent skin contact) or digging out the roots. Make certain you get the entire root, or it will resprout.

If you're particularly sensitive to poison ivy, be extremely careful since all plant parts contain a skin irritant (urushiol). It may be better to resort to herbicides and avoid handling the plants.

Vines growing on trees can be difficult to pull out. Cut the vine at the base and carefully remove it from the tree. Apply glyphosate (Roundup) or triclopyr (Ortho's Brush-B-Gon) to new shoots that emerge from the base of the old plant. Repeat applications of herbicide are usually necessary for complete control.

If you come in contact with poison ivy, wash with soap and cool water immediately. Avoid burning the vines you remove. The smoke contains urushiol, and breathing the smoke or coming in contact with tainted clothing can cause a rash.

Q: How can I get rid of mistletoe in my oak tree?

Mistletoe is a parasitic plant that develops root-like structures called haustoria that spread through the tree branch to which it is attached. If you cut off the mistletoe, it will resprout. However there will be no mature mistletoe present to develop seeds, which is how mistletoe spreads to new branches.

Removing the host branches is a better long-term solution, especially if you can cut the branches at least a foot below where the mistletoe is growing. Keep in mind that most healthy trees can handle a light load of mistletoe.

Mistletoe infecting a major branch or the trunk where it cannot be pruned may be controlled by cutting off the mistletoe flush with the limb or trunk. Then wrap the area with a few layers of wide, black polyethylene to exclude light. Use twine or tape to secure the plastic to the limb, but do not wrap it too tightly or the branch may be damaged. Broadleaf mistletoe requires light and will die within a couple of years without it.

It may be necessary to repeat this treatment, especially if the wrapping becomes detached or if the mistletoe does not die.

Cutting the mistletoe out of an infested tree each winter, even without wrapping, is better than doing nothing at all. Even though the parasite will grow back, spread is reduced because broadleaf mistletoe must be several years old before it can bloom and produce seed.

In some cases it is best to remove severely infested trees entirely because they are usually a source of mistletoe seeds.

Tom Bruton is a master gardener with the Duval County Extension Service and the University of Florida/IFAS.